The iWALK Crutch - A Total Game Changer.

Independent research proves it

By Evrim S. Altinkaynak, PhD

We understand you might be skeptical when we say the iWALK is the best crutch you’ll ever use, so we’ve provided independent research to back it up!

Click below to download our clinical research dossier.

iWALKFree is offering research grant to eligible public and private institutions of higher education. Find out more HERE.

Advantages of the iWalk Crutch

Compared to crutches or knee scooters

Click on any advantage below for more information.

It is generally understood that the incidence of developing a deep vein thrombosis (DVT) is higher for patients with lower limb non-weight bearing injuries than for the general population (Saragas et al., 2014; Sullivan et al., 2019). For instance, the prevalence of DVT for patients after a foot and ankle surgery were reported to be as high as 32% (Saragas et al., 2014). The risk of DVT is a direct consequence of immobilization for prolonged periods of time due to the reduction in blood flow (Bleeker et al., 2004; Bradley et al., 2022; Ciufo et al., 2019), muscle pump activity (Dewar et al., 2021; Dewar & Martin, 2020) and muscle oxygen delivery (Bradley et al., 2023) for both knee scooters and crutches when compared to normal unassisted walking. Such prior studies support research that have directly shown blood pooling in the lower extremity as a consequence of crutch usage with an increase in calf circumference after a prolonged period of time (Tesch et al., 2004). A published study comparing the blood flow and vessel dimensions after using the HFC, knee scooter and crutches found that unlike knee scooters and crutches, the HFC did not lead to statistically significant reductions in popliteal blood flow and vessel dimension when compared to unassisted normal walking (Bradley et al., 2022). In addition to this, the HFC leads to a heightened level of muscle activity in the injured limb explaining the increased blood flow observed using the HFC due to prior studies that have shown the influence muscle activity has on blood flow (Bradley & Hernandez, 2011; Dewar et al., 2021; Dewar & Martin, 2020; Reb et al., 2021). Furthermore, crutches have been shown to elevate deoxygenated hemoglobin in the vastus lateralis, biceps femoris and lateral gastrocnemius muscles beyond levels typically measured for unassisted walking (Bradley et al., 2023). An increase of deoxygenated hemoglobin has been associated with the risk of developing a DVT in prior studies (Yamaki et al., 2011). This result is impactful as it has been argued in prior research that a flexed knee angle leads to increasing the risk of DVTs (Ciufo et al., 2019; Reb et al., 2021). For instance, subjects who sat for a prolonged period of time were shown to be more likely to develop a DVT according to one study (Kurosawa et al., 2022). Use of knee scooters, like sitting, fixes the knee angle to be approximately 90 degrees for a prolonged period of time. Another prior study argued that knee scooter users are more susceptible to developing a DVT due to the knee flexion (Ciufo et al., 2019). Furthermore, this study concluded that knee flexion had a direct impact on blood flow due to the reduction in blood flow observed using a knee scooter (Ciufo et al., 2019). However, these studies were limited in that it did not consider the decrease in muscle activity when both sitting as well as ambulating using the knee scooter as muscle pump activity is crucial for preventing stasis (Reb et al., 2021). Like scooters, the HFC has a knee flexion angle that is approximately 90 degrees. However, unlike knee scooters and crutches, the HFC does not lead to a statistically significant reduction in blood flow and muscle activity (Bradley et al., 2022; Dewar et al., 2021; Dewar & Martin, 2020). This result shows that the negative effects of knee flexion can be mitigated with the HFC and that muscle activity has a greater impact on blood flow and reducing the risk of DVT than knee flexion.

A study published in Foot and Ankle Orthopaedics compared the blood flow and vessel dimensions following ambulation using the HFC, knee scooter and crutches for 40 participants (Bradley et al., 2022). This study found that the HFC led to a significantly lower decline in blood flow when compared to both knee scooters and crutches in popliteal blood flow and vessel dimension (Bradley et al., 2022). The results of this study corroborate the findings of other prior works which reported a significant decline in blood flow for knee scooters (Ciufo et al., 2019) with crutches leading to the greatest decrease (Reb et al., 2021). The increased blood flow observed with the HFC was attributed to the heightened muscle activity with the HFC in the suspended limb compared to both crutches and knee scooters (Bradley et al., 2022; Dewar et al., 2021; Dewar & Martin, 2020). This study along with other research have shown that muscle activity has a major impact on blood flow (Bradley et al., 2022; Bradley & Hernandez, 2011; Reb et al., 2021).

A study published in Foot and Ankle Orthopaedics compared the blood flow and vessel dimensions following ambulation using the HFC, knee scooter and crutches for 40 participants (Bradley et al., 2022). This study found that the HFC led to a significantly lower decline in blood flow when compared to both knee scooters and crutches in popliteal blood flow and vessel dimension (Bradley et al., 2022). The results of this study corroborate the findings of other prior works which reported a significant decline in blood flow for knee scooters (Ciufo et al., 2019) with crutches leading to the greatest decrease (Reb et al., 2021). The elevation in blood flow with the HFC can be attributed to the heightened muscle activity with the HFC in the suspended limb compared to both crutches and knee scooters (Bradley et al., 2022; Dewar et al., 2021; Dewar & Martin, 2020). This study along with other research have shown that muscle activity has a major impact on blood flow (Bradley et al., 2022; Bradley & Hernandez, 2011; Reb et al., 2021). Reductions in blood flow is a major concern during a period of immobilization. Research shows that blood flow can be reduced by 61% after 8 hours of constant sitting (Kurosawa et al., 2022). When poor blood flow continues as a consequence of prolonged immobilization, it can present as deep vein thrombosis (DVT) in the lower extremities (Broderick et al., 2009; Faghri et al., 1997; McLachlin et al., 1960; Vinay et al., 2021) and cause pain, venous congestion and life-threatening pulmonary embolisms (PE) (Bradley et al., 2022). In particular, blood pooling of more than 48 hours was associated with developing a DVT in one prior study (Tesch et al., 2004). Reduced blood flow can also impact oxygen delivery to the injured muscle and bone which is important for healing (Lu et al., 2013; Rodriguez et al., 2008). In particular, one study found that muscle oxygen saturation to the muscles of the lower extremity was reduced with crutches as a result of the lower blood flow for crutches (Bradley et al., 2023) as was also argued in a previous study that measured blood flow for crutches, knee scooter and the HFC (Bradley et al., 2022). On the other hand, the HFC in both studies far exceeded crutches in blood flow and oxygen delivery with levels similar to normal unassisted walking (Bradley et al., 2022; Bradley et al., 2023). Popliteal venous blood flow of both crutches and knee scooters were impaired (Bradley et al., 2022). A fixed knee angle has been believed to have a direct impact on increasing the risk of developing a deep vein thrombosis in some prior studies (Bleeker et al., 2004; Ciufo et al., 2019). In particular, one study found that the flexed knee position during knee scooter use led to a significant reduction in blood flow (Ciufo et al., 2019). However, these aforementioned negative effects of knee flexion angle can be negated with the HFC due to the increased muscle activity in the suspended limb (Bradley et al., 2022; Dewar et al., 2021; Dewar & Martin, 2020). Moreover, these studies demonstrated that muscle activity in the suspended limb has a greater impact on blood flow than the knee flexion angle (Bradley et al., 2022; Dewar et al., 2021; Dewar & Martin, 2020) which is in agreement with another study arguing a similar conclusion (Reb et al., 2021) thereby changing the notion that knee flexion angle alone leads to developing a deep vein thrombosis.

It is widely accepted that wound and bone healing as well as basic cellular processes rely on muscle oxygen delivery to the injured site (Lu et al., 2013; Rodriguez et al., 2008; Sen, 2009). For instance, the aerobic metabolism responsible of generating adenosine triphosphate (ATP) in the mitochondria require oxygen (Ferretti et al., 2022; Sen, 2009) as well as various enyzmes that play a vital role in healing (Zhang et al., 2002). Impairment in bone repair are also observed when there is a lack of cyclooxygenase-2 activity (Zhang et al., 2002). Finally, if there is a reduction in tissue oxygen, this may impact collagen synthesis (Fong, 2009). Improving oxygen delivery to the injured limb has also implications in reducing muscle atrophy and the risk of developing a deep vein thrombosis which is a common issue with immobilization (Bradley et al., 2023; Sullivan et al., 2019; Yamaki et al., 2011). A direct study measured muscle oxygen saturation during ambulatory walking and while using crutches, knee scooter and the HFC using a relatively large sample size of 38 participants (Bradley et al., 2023). Infrared spectroscopy sensors were placed on the vastus lateralis, biceps femoris, and lateral gastrocnemius muscles of the non-weight bearing limb. This study found that there were no significant changes in muscle oxygen saturation with the HFC when compared to unassisted walking, while there were statistically significant declines in oxygen delivery for crutches in the bicep femoris and lateral gastrocnemius muscles (Bradley et al., 2023). 

Dr. Jason Wilken, a recognized expert in walking stability and falls in the Department of Physical Therapy and Rehabilitation Science at the University of Iowa conducted a research study that directly compared the walking stability of both the HFC and crutches using the range of angular momentum as the outcome measure for both mobility devices with or without a walking boot (Wiederien et al., 2023). This study found that HFC users had a significantly lower range of whole-body angular momentum compared to crutch users in both conditions (Wiederien et al., 2023). The range of whole-angular momentum is crucial for balance control during human locomotion (Herr & Popovic, 2008). In particular, a larger range of whole-body angular momentum in the sagittal plane has been shown to be associated with an increased risk of falling and poor balance during gait in several prior studies (Bennett et al., 2010; Herr & Popovic, 2008; Nolasco et al., 2019; Nott et al., 2014; Pickle et al., 2017; Pickle et al., 2014; Robert et al., 2009; Sheehan et al., 2015; Silverman & Neptune, 2011; Silverman et al., 2014; Vistamehr et al., 2016). Based on such prior research that provides the direct impact angular momentum has on walking stability coupled with the study that has shown that the angular momentum is significantly greater using crutches compared to the HFC, this proved that patients are at more risk of falling when using crutches than the HFC (Wiederien et al., 2023) which has been reported as a common concern with mobility device use (Hefflin et al., 2004). For instance, falling is known to be a common concern for knee scooters in literature (Rahman et al., 2020). Because the HFC recruits both legs and arms during locomotion similar to normal unassisted gait, this study also found that the HFC leads to an angular momentum pattern closest to normal unassisted gait that is sinusoidal with positive peaks corresponding to the rapid advancement of the swing limb of each limb (Wiederien et al., 2023). In contrast, crutches were shown to have a negative angular momentum the first half of the gait cycle and subsequently a large positive peak in the last half of the gait cycle as both limbs advance simultaneously (Wiederien et al., 2023). Such a significant difference in angular momentum patterns is associated with an increased risk of falling (Vistamehr et al., 2016). This result corroborates other prior studies which showed that patients feel safer using the HFC (Rambani et al., 2007) and prefer the HFC over crutches (Canter et al., 2023; Martin et al., 2019). The result of this study is impactful as it relates to the overall safety of mobility device choices and can guide medical providers during the prescription of an assistive device for patients who require to remain non-weight bearing due to a lower limb injury.

Because the HFC recruits both legs and arms during locomotion similar to normal unassisted gait, this study also found that the HFC leads to an angular momentum pattern closest to normal unassisted gait that is sinusoidal with positive peaks corresponding to the rapid advancement of the swing limb of each limb (Wiederien et al., 2023). In contrast, crutches were shown to have a negative angular momentum the first half of the gait cycle and subsequently a large positive peak in the last half of the gait cycle as both limbs advance simultaneously (Wiederien et al., 2023). Such a significant difference in angular momentum patterns is associated with an increased risk of falling (Vistamehr et al., 2016).

This result corroborates other prior studies which showed that patients feel safer using the HFC (Rambani et al., 2007) and prefer the HFC over crutches (Martin et al., 2019). The result of this study is impactful as it relates to the overall safety of mobility device choices, and can guide medical providers during the prescription of an assistive device for patients who require to remain non-weight bearing due to a lower limb injury.

The HFC is preferred by 86% of foot and ankle patients over crutches (Martin et al., 2019). This finding is consistent with other prior literature which report participants preferring the HFC over crutches (Wiederien et al., 2023). Patient satisfaction, safety and preference can be a major determinant for compliance to non-weight bearing recommendations (Bateni & Maki, 2005; Faruqui & Jaeblon, 2010; Martin et al., 2019) which is of paramount importance to achieving optimal results and prevent postoperative complications such as wound breakdown, loss of fracture fixation or hardware failure (Chiodo et al., 2016; Gershkovich et al., 2016). Prior research shows that subjects prefer the HFC over both crutches and knee scooters in completing activities of daily life while knee scooters presented a clear limitation in environments that contain stairs or rough terrain (Canter et al., 2023). This study further argued that the preference for the HFC compared to the knee scooter was a result of subjects being unable to climb stairs or complete the stair portion of the ADL course as it was too difficult to carry the scooter over the steps in this course. One other reason why the HFC is favorable among subjects compared to crutches may be explained by the lower exertion, heart rate, energy expenditure and pain scores when using the HFC as shown in various published studies (Canter et al., 2023; Hackney et al., 2022; Martin et al., 2019).

Unlike crutches and knee scooters, the HFC is a hand free mobility device. Thus, activities of daily living (ADLs and IADLs) that are impossible to do with crutches and knee scooters such as shopping, working, cooking, childcare, stairs, etc. are possible with the HFC (Canter et al., 2023). A randomized control trial with 80 patients with both upper and lower limb injuries showed that they were able to complete activities around the house using the HFC (Rambani et al., 2007) and patients had a more positive attitude to life due to the improved independence with the HFC (Barth et al., 2019). This is just one of the reasons why the HFC is preferred over both crutches and knee scooters (Canter et al., 2023; Martin et al., 2019; Wiederien et al., 2023). Researchers Dr. Timmerman and Dr. Reidy at the Department of Kinesiology and Health of Miami University conducted a direct study that aimed to investigate the ability to perform activities of daily living (ADLs) using a HFC compared to crutches and knee scooters (Canter et al., 2023). This study found that subjects preferred the HFC over both crutches and knee scooters during ambulation, stair climbing and activities of daily living while the knee scooter led to a clear disadvantage for stair climbing and on rough terrain (Canter et al., 2023). Furthermore, subjects found the HFC easier to use than crutches and knee scooters and had a lower heart rate, perceived exertion and energy expenditure (Canter et al., 2023).

The HFC improves patient compliance to non-weight bearing restrictions, due to prior research that shows that patients with lower limb injuries prefer a HFC over crutches and the important role patient preference plays on patient compliance (Canter et al., 2023; Martin et al., 2019; Wiederien et al., 2023). In addition, because patients are able to function independently using the HFC with the ability to do activities of daily living (Canter et al., 2023; Rambani et al., 2007), the HFC will lead to better compliance. Published research shows that patients prefer the HFC over crutches and knee scooters when completing activities of daily living (Canter et al., 2023; Martin et al., 2019; Wiederien et al., 2023). Patients with lower extremity injuries have been known to be noncompliant with prescribed weight bearing restrictions while using crutches likely due to the pain, discomfort and limitations of performing activities of daily living (Chiodo et al., 2016; Gershkovich et al., 2016; Kubiak et al., 2013; Martin et al., 2019). However, lack of compliance can lead to secondary injuries and further complications such as wound breakdown, loss of fracture fixation or hardware failure (Gershkovich et al., 2016).

Research proves that the HFC provides statistically significant increases in muscle activity for the hip, quadriceps and calf muscles in the non-weight bearing leg with muscle activity patterns consistent with normal unassisted ambulation in terms of both intensity and activation per EMG recordings (Dewar et al., 2021; Dewar & Martin, 2020). On the other hand, crutches and knee scooters lead to statistically significant reductions in muscle activity in the non-weight bearing leg compared to normal unassisted ambulation as was shown in various prior studies (Clark et al., 2004; Dewar et al., 2021; Dewar & Martin, 2020; Sanders et al., 2018; Seynnes et al., 2008). The heightened level of muscle engagement in the non-weight bearing leg using the HFC compared to crutches has a direct impact on decreasing muscle atrophy, increasing blood flow, reducing the risk of deep vein thrombosis (DVT) and enhancing healing (Bradley et al., 2022; Broderick et al., 2009; Dewar et al., 2021; Dewar & Martin, 2020; Faghri et al., 1997; Rasouli & Reed, 2020; Vinay et al., 2021). Each of these benefits of the heightened muscle activation using the HFC are supported with direct and associated studies in the following sections.

The heightened recruitment of the muscles in the non-weight bearing leg when using the HFC compared to crutches decreases the level of disuse muscle atrophy (Altinkaynak, 2022; Bradley et al., 2022; Dewar et al., 2021; Dewar & Martin, 2020). Prior research shows that the degree a muscle will atrophy is dependent on the activity of the muscle (Clark, 2009; MacLennan et al., 2020; Magill et al., 2019; Sanders et al., 2018). Moreover, the increase in muscle oxygen saturation to the muscles of the non-weight bearing limb while using the HFC can also reduce muscle atrophy after a period of non-weight bearing (Bradley et al., 2023). This is further supported by prior research that shows a muscle fixed in a shorted position atrophies faster than if a muscle is fixed in a lengthened position (Booth, 1982; Booth & Gollnick, 1983). Thus, the knee flexion angle was shown to play an important role in muscle atrophy (Magill et al., 2019). Because the HFC fixes the knee angle at 90° flexion which lengthens the muscle, the muscle atrophy after a period of non-weight bearing is expected to be less compared to crutches that fixes the knee angle at approximately 30° (Altinkaynak, 2022). This could partially explain why crutches have been shown to have led to significant muscle atrophy with reductions in muscle size and strength as well as structural changes in muscle fibers in various prior studies (De Boer et al., 2008; Hather et al., 1992; Tesch et al., 2016).

There is a large body of research that have shown that crutches are attributed to significantly higher energy costs compared to normal unassisted ambulation (Dounis et al., 1980; Holder et al., 1993; Mcbeath et al., 1974; Nielsen et al., 1990; Sankarankutty et al., 1979; Thys et al., 1996). Increased physiological demand has been shown to be an important factor in discontinuance and noncompliance to weight bearing restrictions with crutch use (Bateni & Maki, 2005). Therefore, mobility devices designed to assist ambulation should keep energy expenditure to a minimum while still allowing normal walking speeds and the ability to do their activities of daily living. A study published in the journal of Foot and Ankle Orthopaedics compared the metabolic cost of ambulation using a portable metabolic analyzer for subjects using a HFC, crutches and knee scooter. This study found that the HFC led to substrate utilization most similar to normal unassisted gait with the least amount of aerobic energy while allowing one to use both hands for activities pertaining to daily life (Hackney et al., 2022). Similar to this study, another study was designed to measure the energy expenditure with a portable indirect calorimetry system for the HFC, knee scooter and crutches this time while completing activities that simulate tasks one would complete in daily life. The results of this study suggested that the HFC was the only mobility device that resulted in energy expenditure similar to normal walking while also allowing users to complete all tasks within the validated ADL course (Canter et al., 2023). Immediately after completing the ADL course subjects were asked how difficult they found ambulating with each assistive device using a Likert scale. The results of this data showed that subjects found using the HFC significantly easier than crutches which correlates with the lower energy expenditure measured using the HFC (Hackney et al., 2022) as well as the lower exertion and heart rate reported for HFC users in other prior studies (Bhambani & Clarkson, 1989; Canter et al., 2023; Hackney et al., 2022; Martin et al., 2019).

 

Although crutches are the most prescribed assistive device (Kaye et al., 2000; Martin et al., 2019; Rambani et al., 2007), prolonged use of crutches have been shown to lead to various secondary injuries (Dalton et al., 2002; Manocha et al., 2021). Crutches lead to seven-fold increase in the force that runs through the axilla (Rambani et al., 2007). This increased force at the axilla has been shown to lead to secondary injuries such as axillary artery thrombosis (McFall et al., 2004; Tripp & Cook, 1998) and crutch palsy (Raikin & Froimson, 1997). Other complications as a result of crutch use are carpal tunnel syndrome (Gellman et al., 1988) and shoulder joint degeneration (Shabas & Scheiber, 1986). Because there is no loading of the hands and upper extremity when using a HFC, secondary injuries have not been reported with the HFC. Secondary injuries also occur with knee scooters due to the increased risk of falling (Rahman et al., 2020; Yeoh et al., 2017). The HFC leads to better stability and a lower risk of falling compared to crutches (Wiederien et al., 2023). Due to this, HFC users are less susceptible to fall related injuries increasing the safety of mobility device users.

It is well accepted that limb immobilization effects human brain plasticity (Langer et al., 2012). In particular, it was shown that the cortical thickness (gray matter) of the sensorimotor cortex and fractional anisotropy (white matter) decreased after a period of immobilization which are both responsible for processing somatosensory information and impact motor movement (Langer et al., 2012). Because the HFC is the only mobility device that leads to muscle activity in the non-weight bearing limb consistent with normal walking when compared to crutches and knee scooters (Dewar et al., 2021; Dewar & Martin, 2020), the reorganization of the sensorimotor system as well as the overall effect of remaining non-weight bearing for prolonged periods on human brain plasticity is minimized with the HFC when compared to crutches and knee scooters.

A randomized control trial conducted using 80 patients showed that patients were discharged significantly faster after using a HFC compared with not using the HFC (Rambani et al., 2007). Reductions in muscle atrophy and improvement in blood flow when using a HFC impacts the total recovery time for lower limb injuries with quicker rehabilitation, faster healing and less cases of developing a deep vein thrombosis and pulmonary embolism (Bradley et al., 2022; Dewar et al., 2021; Dewar & Martin, 2020). The increased muscle oxygenation saturation using the HFC via improved blood flow also enhances healing (Bradley et al., 2023; Lu et al., 2013). Crutches cause reductions in cross-sectional area of the quadriceps femoris muscle of about 0.4% per day (Clark et al., 2004). Because the HFC reduces muscle atrophy, the HFC leads to faster therapeutic gains. Moreover, secondary injuries as a result of using crutches or knee scooters falling (Rahman et al., 2020; Yeoh et al., 2017) are nonexistent when using a HFC in addition to the better stability compared to crutches  which all contribute to reducing the recovery times of lower limb injuries (Wiederien et al., 2023).

References

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I

DIRECT RESEARCH

Effect of Crutch and Walking-Boot Use on Whole-Body Angular Momentum During Gait

Robert C. Wiederien, DPT, Wesley J. Gari, SBSE, and Jason M. Wilken, PT, PhD

Summary: iWALK users have a lower risk of falling than people who use crutches. This result has a direct implication on user safety and that the iWALK could reduce further fall related injuries during recovery of a lower limb injury.

“Seventeen participants were evaluated while walking without a crutch (NONE), with SACs, and with an HFC, and walked with and without a walking boot in each crutch condition. The gait pattern used with SACs resulted in significantly greater limb angular velocity (p<.05), and an 84% increase in RAM (whole-body angular momentum) (p<.001) as compared to the HFC… Increased risk of falling and poor balance during gait have been associated with greater RAM in the sagittal plane… The higher RAM with SACs compared to the HFC indicates that patients may be more at risk of falling when using SACs.”

– Assistive Technology – Official Journal of RESNA

Popliteal Blood Flow with Lower-Extremity Injury Mobility Devices

Adam P. Bradley, MS, Alexis S. Roehl, Ryan McGrath, PhD, Joseph Smith, PhD, and Kyle J. Hackney, PhD

Summary: The iWALK unlike knee scooters and crutches leads to blood flow most similar to normal unassisted walking. This increase in blood flow for the lower extremities while using the iWALK reduces the risk of blood clots.

“Participants experienced an increase in popliteal arterial flow from baseline following both walking and HFC, whereas knee scooters and crutches resulted in a decrease in flow compared to walking…Deep Vein Thrombosis (DVT) is a concern with prolonged knee flexion and is associated with decreased popliteal venous flow and stasis …Despite having a flexed knee, venous flow following HFC was not different than walking. The effect of knee flexion in HFC was likely mitigated by its unique ambulation similar to walking gait, given that muscular activity is a major determinant of popliteal venous flow… Clinicians aiming to prevent stasis may consider HFC as a promising ambulation device option during period of unloading.”

– American Orthopedic Foot and Ankle Society

Energy Expenditure and Substrate Utilization with Hands-Free Crutches Compared to Conventional Lower-Extremity Injury Mobility Devices

Kyle J. Hackney, PhD, Adam P. Bradley, MS, Alexis S. Roehl, Ryan McGrath, PhD, and Joseph Smith, PhD

Summary: The energy cost of ambulation using the iWALK is lower compared to crutches. Moreover, the exertion and pain scores are lower with the iWALK than crutches.

“There were significant differences in substrate utilization as evidenced by average respiratory exchange ratio (RER)…There were no differences in RER with the hands-free crutch compared to walking (P=.350). Average RER during crutches was also significantly greater than HFC (P<.001)… Average RER for knee scooters was significantly greater the hands free crutch (P<.001)…Differences in aerobic energy expenditure and comfort during ambulation is critical for safety and ease of use while in the non-weight bearing recovery period. ”

– American Orthopedic Foot and Ankle Society

Patient Preference and Physical Demand for Hands-Free Single Crutch vs. Standard Axillary Crutches in Foot and Ankle Patients

Kevin D. Martin, DO, Alicia M. Unangst, DO, Jeannie Huh, MD and Jamie Chisholm, MBA

Summary: This study proved that 9 out of 10 patients prefer a hands-free crutch (iWALK) over crutches. Patients experienced less discomfort and exertion when using the hands-free crutch compared with crutches.

“The Hands-Free Single Crutch (HFSC) was preferred by 86% of patients. Significantly lower dyspnea scores (2.8 vs 5.3; P<0.001), fatigue scores (2.4 vs 5.5; P<0.001), pre-activity and post-activity change in heart rate (28 vs 46 bpm; P<0.001), and mean post-activity heart rate (107 vs 122 bpm; P<0.001) were found using the HFSC compared with the Standard Axillary Crutches (SACs)… SACs have demonstrated a substantial energy cost compared with normal gait, and they have been also been associated with injury… Selecting an appropriate assistive device is multifactorial and should be patient specific to improve patient compliance and optimize mobility and safety… Understanding physiologic cost, function, fall risk, and overall patient satisfaction could aid healthcare providers in determining an appropriate ambulatory device that is patient specific.”

– American Orthopedic Foot and Ankle Society

Muscle Specific Declines in Oxygen Saturation During Acute Ambulation with Hands-Free and Conventional Mobility Devices

Adam P. Bradley, Alexis S. Roehl, Joseph Smith, Ryan McGrath and Kyle J. Hackney

Summary: The HFC leads to oxygen delivery in the muscles of the non-weight bearing leg similar to normal unassisted walking while crutches reduce oxygen delivery in all the muscles groups. This has significant implications in wound and fracture healing as oxygen delivery is essential for healing, reducing muscle atrophy and the risk of blood clots.

“This study examined muscle oxygen saturation (SmO2) in walking and ambulation with various mobility devices… During each trial, near infrared spectroscopy sensors were placed on the vastus lateralis (VL), biceps femoris (BF), and lateral gastrocnemius (LG) of the right limb. Post-hoc testing determined that when compared to walking, SmO2 declined only in axillary crutches. There were no significant changes in BF SmO2 with HFC… There were no differences in LG SmO2 when compared to walking or when compared to HFC… Oxygen delivery plays a crucial role in wound and fracture healing by generating ATP via aerobic metabolism and stimulating the activity of critical enzymes for repair.”

– Frontiers in Sports and Active Living

A Comparison of Energy Expenditure and Perceived Exertion Between Standard Axillary Crutches, Knee Scooters, and a Hands-Free Crutch

Dillon J. Canter, Daniel J Canter, Paul T Reidy, Tim Finucan, and Kyle L. Timmerman

Summary: The HFC leads to lower heart rate, exertion and energy expenditure when compared to axillary crutches and knee scooters for stair climbing and activity of daily living (ADL). The subjects showed a clear preference towards the HFC. One of the main reasons for this preference was due to knee scooter users being unable to complete the task of stair climbing and ADL course due to the bulkiness/difficulty of carrying the scooter. 

“Ambulation using standard axillary crutches (SAC) is associated with increased energy expenditure and decreased ability to perform activities of daily living (ADLs)…Participants completed an ADL course, and a two-flight stair climb with SAC, HFC, knee scooter (KS) and unassisted walking (UA)… For the ADL course, heart rate (HR) was significantly lower for HFC compared to SAC and KS (p<0.05). Rating of perceived exertion (RPE) for HFC was lower than KS and SAC. For the stair climb task, HFC elicited lower energy expenditure, HR and RPE than SAC. 14 of 20 subjects indicated their preference for HFC… The overall preference for the HFC compared to the KS was driven by the inability to use the KS on a flight of stairs… In contrast, the HFC appears to have better utility overall by enabling assistive benefits across a wider range of environments.”

– PM&R (American Academy of Physical Medicine and Rehabilitation

Effect of Crutch and Walking-Boot Use on Whole-Body Angular Momentum During Gait

Robert C. Wiederien, DPT, Wesley J. Gari, SBSE, and Jason M. Wilken, PT, PhD

Summary: iWALK users have a lower risk of falling than people who use crutches. This result has a direct implication on user safety and that the iWALK could reduce further fall related injuries during recovery of a lower limb injury.

“Seventeen participants were evaluated while walking without a crutch (NONE), with SACs, and with an HFC, and walked with and without a walking boot in each crutch condition. The gait pattern used with SACs resulted in significantly greater limb angular velocity (p<.05), and an 84% increase in RAM (whole-body angular momentum) (p<.001) as compared to the HFC… Increased risk of falling and poor balance during gait have been associated with greater RAM in the sagittal plane… The higher RAM with SACs compared to the HFC indicates that patients may be more at risk of falling when using SACs.”

Use of a Hands-Free Crutch in Patients with Musculoskeletal Injuries

R. Rambani, M. S. Shadid, and S. Goyal

Summary: Patients that use a hands-free crutch are discharged significantly faster than patients who do not use it.

“The average stay of the patients using a hands-free crutch (HFC) was 2.3 days, with a range of 1-5 days. This was much shorter compared with the stay for patients who had similar injuries and had decided not to use this crutch: 4-14 days (average, 6.7 days). This difference was statistically significant (P=0.05)… This not only helps in decreasing the burden on the hospital in terms of the expenses of hospital stay, but also helps the patient to be independent quickly, after an injury… The HFC was associated with a better overall musculoskeletal functional assessment score (P<0.05), better coping, a trend towards better lower extremity function, and with performing activities around the house. The HFC was well accepted, safe, and easy to use. A clear trend for better function with the HFC was seen. SF-36 physical function tended to be better with the HFC (P<0.05)… The HFC is a viable alternative for patients required to be nonweightbearing during ambulation.”

– International Journal of Rehabilitation Research

Alternative Mobilization by Means of a Novel Orthosis in Patients after Amputation

U. Barth, K. Wasseroth, Z. Halloul, F. Meyer

Summary: Patients using an iWALK exhibited improvements in their ability to perform activities of daily living. The iWALK was shown to provide emotional and psychological benefits and was well accepted.

“The successful application of the “hand free” device “iWALK Crutch” under the listed clinical condition thus suggest that it is a clear alternative of postoperative rehabilitation in the diagnosis of a surgically treated diabetic foot gangrene after minor amputation ……in addition to giving the patient as much independence as possible, this also made the patient feel positive about life again….overall the iWALK orthosis was considered by the patient to be of a high quality and comfortable, and it was completely accepted, which also helped to motivate the patient with mobilization.”

– Thieme Group

WARNING – the following article contains graphic images.

I

ASSOCIATED RESEARCH

Pedal Musculovenous Pump Activation Effectively Counteracts Negative Impact of Knee Flexion on Human Popliteal Venous Flow

C. W. Reb, E. T. Haupt, R. A. Vander Griend, and G. C. Berlet

Summary: Crutches with slight knee flexion leads to the greatest decrease in blood flow compared to upright and knee scooter positioning. Muscle activity has been shown to have a greater impact on blood flow than knee flexion angle which has implications in blood clotting.

“There was a significant decrease in pedal musculovenous pump (PMP) time-averaged peak velocity (TAPV) when comparing upright to crutch positioning, and this decrease was slightly more when comparing upright to knee scooter positioning (knee at 90°)… Knee flexion was found to have a variable but generally small negative effect on popliteal venous flow. The trend was toward greater flow impedance with increasing knee flexion… PMP activation where permissible is a potentially valuable venous stasis countermeasure to consider.”

– SAGE Journals

Skeletal muscle responses to lower limb suspension in humans

B. M. Hather, G. R. Adams, P. A. Tesch, and G. A. Dudley

Summary: Crutches lead to decreases in muscle size.

“Magnetic resonance images pre- and post-ULLS showed that thigh muscle cross-sectional area (CSA) decreased (P less than 0.05) 12% in the suspended left lower limb… The three vastus muscles showed similar decreases of approximately 16% (P less than 0.05). The apparent atrophy in the leg was due mainly to reductions in CSA of the soleus (-17%) and gastrocnemius muscles (-26%). Biopsies of the left vastus lateralis pre- and post-ULLS showed a 14% decrease (P less than 0.05) in average fiber CSA. The decrease was evident in both type I (-12%) and II (-15%) fibers.”

– National Library of Medicine

Adaptations to unilateral lower limb suspension in humans

G. A. Dudley, M. R. Duvoisin, G. R. Adams, R. A. Meyer, A. H. Belew, and P. Buchanan

Summary: Reductions in muscle strength occur after 6 weeks of crutch use.

“Strength of the KE of the suspended left limb was reduced (p less than 0.05) 21 and 15%, respectively, after ULLS and 4 d later. Average muscle CSA of the left KE decreased (p less than 0.05) 16%… Average muscle CSA of the KE of the suspended limb was 17% less (p less than 0.05) than that of the non-suspended limb. Average muscle CSA of the AE, likewise, was smaller (18%, p less than 0.05) in the left than right leg after ULLS. Maximal integrated EMG of VL and overall mean power frequency of GM and SL for submaximal isometric actions were both decreased (p less than 0.05) post-ULLS.”

– National Library of Medicine

Early structural adaptations to unloading in the human calf muscles

O. R. Seynnes, C. N. Maganaris, M. D. de Boer, P. E. di Prampero, and M. V. Narici

Summary: Using crutches cause structural changes in muscle fibers that reduce muscle function.

“Soleus (SOL), gastrocnemius medialis (GM) and lateralis muscle (GL) volume decreased by 5%, 6% and 5%, respectively (P < 0.05), on day 14, and by 7% (SOL), 10% (GM) and 6% (GL) on day 23. In GL, pennation angle and fascicle length were reduced by 3% (P < 0.05) and 2% (NS), respectively, on day 14, and by 5% (P < 0.05) and 4% (P < 0.05), respectively, on day 23. Consequently, GL physiological cross-sectional area (PCSA) declined by 3% (P < 0.05) on day 14, but did not further decrease on day 23. Similarly, the 7% (P < 0.05) loss in GL force/PCSA observed on day 14 persisted until the end of the unloading period.”

– National Library of Medicine

Time course of muscular, neural and tendinous adaptations to 23 day unilateral lower-limb suspension in young men

M. D. de Boer, C. N. Maganaris, O. R. Seynnes, M. J. Rennie, and M. V. Narici

Summary: Crutches lead to reductions in tendon collagen synthesis. This can influence the ability to transfer force from muscle contractions to skeleton.

“After 14 and 23 days (i) knee extensor torque decreased by 14.8 +/- 5.5% (P < 0.001) and 21.0 +/- 7.1% (P < 0.001), respectively; (ii) voluntary activation did not change; (iii) knee extensor cross-sectional area decreased by 5.2 +/- 0.7% (P < 0.001) and 10.0 +/- 2.0% (P < 0.001), respectively; fascicle length decreased by 5.9% (n.s.) and 7.7% (P < 0.05), respectively, and by 3.2% (P < 0.05) and 7.6% (P < 0.01); (iv) tendon stiffness decreased by 9.8 +/- 8.2% (P < 0.05) and 29.3 +/- 11.5% (P < 0.005), respectively, and Young’s modulus by 9.2 +/- 8.2% (P < 0.05) and 30.1 +/- 11.9% (P < 0.01), respectively, with no changes in the controls. Hence, ULLS induces rapid losses of knee extensor muscle size, architecture and function.”

– The Journal of Physiology

Bone loss from the human tibia epiphysis during 24 days of unilateral lower limb suspension

J. Rittweger, K. Winwood, O. Seynnes, M. de Boer, D. Wilks, R. Lea, M. Rennie, and M. Narici

Summary: Crutches lead to bone loss comparable to those seen with bed rest. Losses in bone mineral content can result in decreased bone strength and increased risk of fracture as well as side effects such as high calcium levels in the blood and kidney stones.

“After 21 days of unilateral lower limb suspension (ULLS), bone mineral content of the peripheral portion of the epiphysis of the suspended tibia was reduced by 0.89 ± 0.48% (from 280.9 ± 34.5 to 278.4 ± 34.2 mg mm−1, P<0.001)… In the peripheral epiphyseal portion, significant bone loss (by 0.32 ± 0.54%, P = 0.045) occurred as early as day 7 of ULLS… Our findings suggest that in its extent bone loss in ULLS resembles the bone loss induced by bed rest.”

– The Journal of Physiology

One-leg inactivity induces a reduction in mitochondrial oxidative capacity, intramyocellular lipid accumulatio and reduced insulin signaling upon lipid infusion: a human study with unilateral limb suspension

L. Bilet, E. Phielix, T. van de Weijer, A. Gemmink, M. Bosma, E. Moonen-Kornips, J. A. Jorgensen,G. Schaart, D. Zhang, K. Meijer, M. Hopman, M. K. C. Hesselink, D. M. Ouwens, G. I. Shulman, V. B. Schrauwen-Hinderling, P. Schrauwen

Summary: Crutches lead to low mitochondrial oxidative capacity and reduced insulin sensitivity that are common denominators of chronic metabolic disorders, like obesity and type 2 diabetes.

“In vivo, mitochondrial oxidative capacity, assessed by phosphocreatine (PCr)-recovery half-time, was lower in the inactive vs active leg. Ex vivo, palmitate oxidation to 14CO2 was lower in the suspended leg vs the active leg; however, this did not result in significantly higher [14C]palmitate incorporation into triacylglycerol. The reduced mitochondrial function in the suspended leg was, however, paralleled by augmented intramyocellular lipid content in both musculus tibialis anterior and musculus vastus lateralis, and by increased membrane bound protein kinase C (PKC) θ. Finally, upon lipid infusion, insulin signalling was lower in the suspended vs active leg… This demonstrates the importance of mitochondrial oxidative capacity and muscle fat accumulation in the development of insulin resistance in humans.”

– Diabetologia

Impact of knee scooter flexion position on venous flow rate

D. J. Ciufo, MD, M. R. Anderson, DO, and J. F. Baumhauer, MD, MPH

Summary: Knee scooters demonstrate a significant decrease in blood flow rate. Decreased blood flow is a known risk factor of blood clots.

“Measurements of subjects while standing and on the knee scooter demonstrated a significant decrease in mean velocity (6.5 vs 3.2 cm/s, P < .01) and volumetric flow rate (227.8 vs 106.2 mL/min, P < .01) while subjects were using the scooter… Our findings demonstrated a statistically significant decrease in volumetric flow rate in subjects using a knee scooter device with a flexed knee… Suggesting that the scooter could pose a risk of DVT formation.”

– SAGE Journals

Energy cost of ambulation with crutches

S. V. Fisher and R. P. Patterson

Summary: Crutches increase the energy needed to ambulate as compared to normal walking.

“The energy cost (oxygen consumption) VO2.wt-1 (ml.min-1.kg-1) of ambulating with underarm crutches compared to normal walking was approximately twice as great. The heart rate (HR) and VO2 for any given rate of vertical rise tested was less with crutch stair climbing than with crutch walking. There was no difference in VO2 or HR when ambulating with underarm compared to forearm (Lofstrand) crutches.”

– National Library of Medicine

Post-Operative Use of the Knee Walker After Foot and Ankle Surgery: A Retrospective Study

Jane Yeoh MD FRCSD, David Ruta MD, David Richardson, MD, Susan Ishikawa MD, Benjamin Gear MD, Dlayton Bettin MD

Summary: Knee scooters were shown to lead to a significant number of falls with a high percentage of knee scooter users falling multiple times.

“The goal of this study is to quantify and describe patient use of knee walkers after foot and ankle surgery in the group practice of foot and ankle surgeons at multiple sites and a single institution. Primary endpoints include occurrence of falls, frequency of falls, and injury……..44% fell while using the knee walker, and nearly two-thirds (65%) of those who fell reported multiple falls….”

– SAGE Journals

I

RESEARCH REVIEW

Prospective Clinical Evaluation Comparing Standard Axillary Crutches versus the Hands Free Crutch

A Dalton, D.Maxwell, C.M. Borkhoff, H.J. Kreder
University of Toronto, Sunnybrook & Women’s College Health Sciences Centre

Summary: Patients experience better overall function when they were able to use their hands while being non-weight bearing for lower extremity injuries with the hands-free crutch.

“Activities of daily living were easier to accomplish with the HFC (p=0.07). None of the patients found the HFC to be uncomfortable, while 2/6 found the SAC to be uncomfortable… The HFC was associated with a better overall MFA score (p<0.05), better coping (p<0.05), and a trend toward better lower extremity function and activities around the house (p=0.07). SF-36 physical function tended to be better with the HFC (p=0.08) in addition to SF-36 vitality (p=0.07). The HFC was well-accepted, safe and easy to use. There was a clear trend for better function with the HFC.”

– University of Toronto

Evaluation of Crutch Energetics Using Standard and Hands Free Crutches

A.Nagpurkar, A. Troelier
University of Guelph, Clinical Biomechanics

Summary: Crutches lead to higher energy expenditure compared to a hands-free crutch.

“Activities of daily living were easier to accomplish with the HFC (p=0.07). None of the patients found the HFC to be uncomfortable, while 2/6 found the SAC to be uncomfortable… The HFC was associated with a better overall MFA score (p<0.05), better coping (p<0.05), and a trend toward better lower extremity function and activities around the house (p=0.07). SF-36 physical function tended to be better with the HFC (p=0.08) in addition to SF-36 vitality (p=0.07). The HFC was well-accepted, safe and easy to use. There was a clear trend for better function with the HFC.”

– University of Guelph

A Hands-free Approach to Patient Mobility: Presenting the Case for a Hands-free Crutch

D. Parker, J. Davis

Summary: A hands-free crutch improves compliance to non-weight bearing recommendations as compared to crutches.

“Crutches can prove awkward and painful for many patients and offers only limited mobility, particularly on stairs. This sometimes causes the patient to ‘cheat’ by putting weight on the affected limb from time to time or discarding their crutches before the required period outlined by their consultant / practitioner… Not only is the resulting lack of mobility frustrating for the patient, crutches may also result in a prolonged hospital stay, which is a drain on resources and may even affect the patient’s feelings of well-being, and in turn, hold back their recovery… With a hands-free crutch, they can, for the most part, get on with life while being NWB, thus their injuries heal which speeds up their recovery by improving their feelings of well-being. The hands-free crutch allows the injured lower leg to be rested on a moulded shelf and strapped into position. This means that the device actively ensures that patients follow their NWB instruction and do not set back their recovery putting weight on the affected leg.”

– Dave Parker, Senior Orthopaedic Practitioner at the Royal Glamorgan Hospital

Mobility Device Use in the United States – Functional Limitations of Crutch Users

H. Stephen Kaye, T. Kang, M. P. LaPlante
National Institute on Disability and Rehabilitation Research, Disability Statistics Report 14

Summary: Crutch users require assistance in performing activities of daily living (ADLs and IADLs).

“81.8% of crutch users report functional limitation… A majority of crutch users have instrumental activities of daily living (IADL) limitations (62.2%), most of whom need assistance (55.7%).”

– University of California

Comparison of Subjective and Physical Function Outcomes Using Axillary Crutches and a “Hands-Free Crutch”, in Comparison to No Crutch, for Mobility

G. A. Lim, T. D. MacLeaod
California State University, Sacramento Department of Physical Therapy

Summary: Functional outcomes were better using the hands-free crutch compared to crutches and was preferred over crutches.

“During the stair climbing test and timed-up-and-go test, subjects trended towards being faster with the hands-free crutch than the axillary crutches… Functional outcomes were better using the hands-free crutch in comparison to the more standard axillary crutches while performing clinical outcome measures of activity…The majority of subjects preferred the hands-free crutch while performing the stair climbing test and 6-minute-walk-test.”

– California State University

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